Design and Validation of a Test Rig to Simulate High Rainfall Events for Infiltration Studies of Permeable Pavement Systems

This paper presents the design and validation of a relatively cost-effective test rig to simulate high rainfall events; such a rig offers a great opportunity for conducting studies (e.g., high infiltration studies) that require high intensity of rainfall on pervious pavements and other permeable systems. The calibration of the test rig, which produced more than 600 mm/h rainfall intensity, was successful. A simple method of using digital photography to capture raindrops and determine raindrop diameter was developed and used successfully to determine the drop size of simulated rainfall by the test rig. Results obtained by this method indicated that the raindrop diameter varied from 0.69-8.97 mm, which was consistent with the high rainfall intensity generated by test rig. Categorization of raindrop size according to Wilson Bentley's classification showed 1.84, 6.42, 33.95, 26.61, and 31.19% for very small, small, medium, large, and very large drops, respectively, which was considered consistent with the relatively high rainfall intensity generated by the test rig. DOI: 10.1061/(ASCE)IR.1943-4774.0000446. (C) 2012 American Society of Civil Engineers.